Arecibo observed near-Earth asteroid (505657) 2014 SR339 using its NASA-funded planetary radar system on February 9, 2018. Radar images reveal 2014 SR339 to have a lumpy, elongated shape at least 1.5 km long and a rotation consistent with the 8.7 hour period determined from optical lightcurves (B.D. Warner, MoreData!). At its closest approach on February 7, the asteroid was 0.054 AU, or about 21 times the Earth-Moon distance, away from Earth. 2014 SR339 was discovered on September 20, 2014 by the NEOWISE infrared spacecraft, which originally suggested its diameter was about 1 km.

About Arecibo
The Arecibo Planetary Radar Program is funded by NASA’s Near-Earth Object Observations Program through a grant to Universities Space Research Association (USRA), from the Near-Earth Object Observations program. The Arecibo Observatory is a facility of the National Science Foundation operated under cooperative agreement by SRI International, USRA, and Universidad Metropolitana.

About NASA PDCO
NASA's Planetary Defense Coordination Office is responsible for finding, tracking and characterizing potentially hazardous asteroids and comets coming near Earth, issuing warnings about possible impacts, and assisting coordination of U.S. government response planning, should there be an actual impact threat.

About USRA
Founded in 1969, under the auspices of the National Academy of Sciences at the request of the U.S. Government, the Universities Space Research Association (USRA) is a nonprofit corporation chartered to advance space-related science, technology and engineering. USRA operates scientific institutes and facilities, and conducts other major research and educational programs, under Federal funding. USRA engages the university community and employs in-house scientific leadership, innovative research and development, and project management expertise. More information about USRA is available at www.usra.edu.